HiLyte™ Fluor 680 acid, SE is an excellent amine-reactive fluorescent labeling dye that generates the protein conjugates that are only slightly red-shifted compared to those of Cy5.5 dyes, resulting in an optimal match to filters designed for Cy5.5 dyes. Fluorescence emission of HiLyte™ Fluor 680 is well separated from that of other commonly used red fluorophores, such as TAMRA, R-phycoerythrin and HiLyte™ Fluor 647 dyes, making it ideal for three- and four-color labeling. Extinction Coefficient (M-1cm-1): 190,000 Fluorescence quantum yield: 0.36 Fluorescence Life Time (ns): 1.1